Blue is a rare colour on River Song, so rare in fact that I can only think of one other episode, the first part to this story compilation, The Impossible Astronault, where River wears any variation on this colour.
But the blue River is wearing isn’t just any blue, it’s Tardis Blue.
Tardis Blue is a colour that has strong associations with The Doctor, he owns this colour.
If you’re the sort of person who reads WAY to much into this sort of thing, and I am exactly one of those people, look at these posts for examples of my over-reading Colour Coding Amy Pond and Colour Coding Clara Oswald.
If you’re anything like me, then it could be argued that River’s overt choice of Tardis Blue is her way of strengthening her position with The Tardis crew, and the mission at hand, as well as claiming some sort of ownership over The Doctor, by dressing head to foot in his favourite colour.
You could do that…
I am going to put my neck on the line and say that I think River’s outfit is a custom made job from the costume department, with that in mind here are some picks I’ve put together to try and capture the essence of River’s look.
River’s dress has a high rounded/turtle neck.
I really liked the colour and fit of this dress.
The colour is darker, but the shape is closer to River’s jacket.
Slight variation of colour, but I was looking for a similar material to the jacket and dress River wears.
River’s not known for her accessories, but here she goes to town with an amazing silver brooch.
River finishes off the look with a pair of super smart court shoes.